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// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
import * as msg from "gen/msg_generated";
import * as flatbuffers from "./flatbuffers";
import { assert } from "./util";
import { close } from "./files";
import * as dispatch from "./dispatch";
import { exit } from "./os";
import { window } from "./window";
import { libdeno } from "./libdeno";
import { formatError } from "./format_error";
const helpMsg = [
"exit Exit the REPL",
"help Print this help message"
].join("\n");
const replCommands = {
exit: {
get() {
exit(0);
}
},
help: {
get() {
return helpMsg;
}
}
};
function startRepl(historyFile: string): number {
const builder = flatbuffers.createBuilder();
const historyFile_ = builder.createString(historyFile);
msg.ReplStart.startReplStart(builder);
msg.ReplStart.addHistoryFile(builder, historyFile_);
const inner = msg.ReplStart.endReplStart(builder);
const baseRes = dispatch.sendSync(builder, msg.Any.ReplStart, inner);
assert(baseRes != null);
assert(msg.Any.ReplStartRes === baseRes!.innerType());
const innerRes = new msg.ReplStartRes();
assert(baseRes!.inner(innerRes) != null);
const rid = innerRes.rid();
return rid;
}
// @internal
export async function readline(rid: number, prompt: string): Promise<string> {
const builder = flatbuffers.createBuilder();
const prompt_ = builder.createString(prompt);
msg.ReplReadline.startReplReadline(builder);
msg.ReplReadline.addRid(builder, rid);
msg.ReplReadline.addPrompt(builder, prompt_);
const inner = msg.ReplReadline.endReplReadline(builder);
const baseRes = await dispatch.sendAsync(
builder,
msg.Any.ReplReadline,
inner
);
assert(baseRes != null);
assert(msg.Any.ReplReadlineRes === baseRes!.innerType());
const innerRes = new msg.ReplReadlineRes();
assert(baseRes!.inner(innerRes) != null);
const line = innerRes.line();
assert(line !== null);
return line || "";
}
// @internal
export async function replLoop(): Promise<void> {
Object.defineProperties(window, replCommands);
const historyFile = "deno_history.txt";
const rid = startRepl(historyFile);
const quitRepl = (exitCode: number) => {
// Special handling in case user calls deno.close(3).
try {
close(rid); // close signals Drop on REPL and saves history.
} catch {}
exit(exitCode);
};
while (true) {
let code = "";
// Top level read
try {
code = await readline(rid, "> ");
if (code.trim() === "") {
continue;
}
} catch (err) {
if (err.message === "EOF") {
quitRepl(0);
} else {
// If interrupted, don't print error.
if (err.message !== "Interrupted") {
// e.g. this happens when we have deno.close(3).
// We want to display the problem.
const formattedError = formatError(libdeno.errorToJSON(err));
console.error(formattedError);
}
// Quit REPL anyways.
quitRepl(1);
}
}
// Start continued read
while (!evaluate(code)) {
code += "\n";
try {
code += await readline(rid, " ");
} catch (err) {
// If interrupted on continued read,
// abort this read instead of quitting.
if (err.message === "Interrupted") {
break;
} else if (err.message === "EOF") {
quitRepl(0);
} else {
// e.g. this happens when we have deno.close(3).
// We want to display the problem.
const formattedError = formatError(libdeno.errorToJSON(err));
console.error(formattedError);
quitRepl(1);
}
}
}
}
}
// Evaluate code.
// Returns true if code is consumed (no error/irrecoverable error).
// Returns false if error is recoverable
function evaluate(code: string): boolean {
const [result, errInfo] = libdeno.evalContext(code);
if (!errInfo) {
console.log(result);
} else if (errInfo.isCompileError && isRecoverableError(errInfo.thrown)) {
// Recoverable compiler error
return false; // don't consume code.
} else {
if (errInfo.isNativeError) {
const formattedError = formatError(
libdeno.errorToJSON(errInfo.thrown as Error)
);
console.error(formattedError);
} else {
console.error("Thrown:", errInfo.thrown);
}
}
return true;
}
// Error messages that allow users to continue input
// instead of throwing an error to REPL
// ref: https://github.com/v8/v8/blob/master/src/message-template.h
// TODO(kevinkassimo): this list might not be comprehensive
const recoverableErrorMessages = [
"Unexpected end of input", // { or [ or (
"Missing initializer in const declaration", // const a
"Missing catch or finally after try", // try {}
"missing ) after argument list", // console.log(1
"Unterminated template literal" // `template
// TODO(kevinkassimo): need a parser to handling errors such as:
// "Missing } in template expression" // `${ or `${ a 123 }`
];
function isRecoverableError(e: Error): boolean {
return recoverableErrorMessages.includes(e.message);
}
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